I have a job and I also sell designs online using Redbubble where they give me a percentage of sales. Do I have to file as self employed?

I had two PT jobs this year. My husband had three FT jobs. My earnings on Redbubble are approximately 1,300$. I don't know how to go about filling our taxes. 

I'm not even sure if we can file jointly or do we have to do it separately because of Redbubble earnings.